In the United States, dangerous goods are often indicated by diamond-shaped signage on the item (see NFPA 704), its container, or the building where it is stored. The color of each diamond indicates its hazard, e.g., flammable is indicated with red, because fire and heat are generally of red color, and explosive is indicated with orange, because mixing red (flammable) with yellow (oxidizing agent) creates orange. A nonflammable or nontoxic gas is indicated with green, because all compressed air vessels are this color in France after World War II, and France was where the diamond system of hazmat identification originated.

Mitigating the risks associated with hazardous materials may require the application of safety precautions during their transport, use, storage and disposal. Most countries regulate hazardous materials by law, and they are subject to several international treaties as well. Even so, different countries may use different class diamonds for the same product. For example, in Australia, Anhydrous Ammonia UN 1005 is classified as 2.3 (Toxic Gas) with sub risk 8 (Corrosive), whereas in the U.S. it is only classified as 2.2 (Non Flammable Gas).

People who handle dangerous goods will often wear protective equipment, and metropolitan fire departments often have a response team specifically trained to deal with accidents and spills. Persons who may come into contact with dangerous goods as part of their work are also often subject to monitoring or health surveillance to ensure that their exposure does not exceed occupational exposure limits.

Laws and regulations on the use and handling of hazardous materials may differ depending on the activity and status of the material. For example, one set of requirements may apply to their use in the workplace while a different set of requirements may apply to spill response, sale for consumer use, or transportation. Most countries regulate some aspect of hazardous materials.

Dangerous goods are divided into nine classes (in addition to several subcategories) on the basis of the specific chemical characteristics producing the risk.[2]

Note: The graphics and text in this article representing the dangerous goods safety marks are derived from the United Nations-based system of identifying dangerous goods. Not all countries use precisely the same graphics (label, placard and/or text information) in their national regulations. Some use graphic symbols, but without English wording or with similar wording in their national language. Refer to the Dangerous Goods Transportation Regulations of the country of interest.

Information on this graphic changes depending on which, "Division" of explosive is shipped. Explosive Dangerous Goods have compatibility group letters assigned to facilitate segregation during transport. The letters used range from A to S excluding the letters I, M, O, P, Q and R. The example above shows an explosive with a compatibility group "A" (shown as 1.1A). The actual letter shown would depend on the specific properties of the substance being transported.

2.2 Non-Flammable Gases: Gases which are neither flammable nor poisonous. Includes the cryogenic gases/liquids (temperatures of below -100 °C) used for cryopreservation and rocket fuels, such as nitrogen, neon, and carbon dioxide.

The Australian Dangerous Goods Code, seventh edition (2008) complies with international standards of importation and exportation of dangerous goods in line with the UN Recommendations on the Transport of Dangerous Goods. Australia uses the standard international UN numbers with a few slightly different signs on the back, front and sides of vehicles carrying hazardous substances. The country uses the same "Hazchem" code system as the UK to provide advisory information to emergency services personnel in the event of an emergency.

New Zealand's Land Transport Rule: Dangerous Goods 2005 and the Dangerous Goods Amendment 2010 describe the rules applied to the transportation of hazardous and dangerous goods in New Zealand. The system closely follows the United Nations Recommendations on the Transport of Dangerous Goods[4] and uses placards with Hazchem codes and UN number on packaging and the transporting vehicle's exterior to convey information to emergency services personnel.

Drivers that carry dangerous goods commercially, or carry quantities in excess of the rule's guidelines must obtain a D (dangerous goods) endorsement on their driver's licence. Drivers carrying quantities of goods under the rule's guidelines and for recreational or domestic purposes do not need any special endorsements.[5]

Transportation of dangerous goods (hazardous materials) in Canada by road is normally a provincial jurisdiction.[6] The federal government has jurisdiction over air, most marine, and most rail transport. The federal government acting centrally created the federal transportation of dangerous goods act and regulations, which provinces adopted in whole or in part via provincial transportation of dangerous goods legislation. The result is that all provinces use the federal regulations as their standard within their province; some small variances can exist because of provincial legislation. Creation of the federal regulations was coordinated by Transport Canada. Hazard classifications are based upon the UN Model.

The European Union has passed numerous directives and regulations to avoid the dissemination and restrict the usage of hazardous substances, important ones being the Restriction of Hazardous Substances Directive and the REACH regulation. There are also long-standing European treaties such as ADR and RID that regulate the transportation of hazardous materials by road, rail, river and inland waterways, following the guide of the UN Model Regulation.

European law distinguishes clearly between the law of dangerous goods and the law of hazardous materials. The first refers primarily to the transport of the respective goods including the interim storage, if caused by the transport. The latter describes the requirements of storage (including warehousing) and usage of hazardous materials. This distinction is important, because different directives and orders of European law are applied.

The United Kingdom (and also Australia, Malaysia, and New Zealand) use the Hazchem warning plate system which carries information on how an emergency service should deal with an incident. The Dangerous Goods Emergency Action Code List (EAC) lists dangerous goods; it is reviewed every two years and is an essential compliance document for all emergency services, local government and for those who may control the planning for, and prevention of, emergencies involving dangerous goods. The latest 2015 version is available from the National Chemical Emergency Centre (NCEC) website.[7]

Due to the increase in the threat of terrorism in the early 21st century after the September 11, 2001 attacks, funding for greater hazmat-handling capabilities was increased throughout the United States, recognizing that flammable, poisonous, explosive, or radioactive substances in particular could be used for terrorist attacks.

The U.S. Occupational Safety and Health Administration (OSHA) regulates the handling of hazardous materials in the workplace as well as response to hazardous-materials-related incidents, most notably through Hazardous Waste Operations and Emergency Response (HAZWOPER).[8] regulations found at 29 CFR 1910.120.

In 1984 the agencies OSHA, EPA, USCG, NIOSH jointly published the first Hazardous Waste Operations and Emergency Response Guidance Manual[8] which is available for download, or can be purchased from the US Government Printing Office, Pub. 85-115.[9]

Following the UN Model, the DOT divides regulated hazardous materials into nine classes, some of which are further subdivided. Hazardous materials in transportation must be placarded and have specified packaging and labelling. Some materials must always be placarded, others may only require placarding in certain circumstances.[clarification needed]

Different standards usually apply for handling and marking hazmats at fixed facilities, including NFPA 704 diamond markings (a consensus standard often adopted by local governmental jurisdictions), OSHA regulations requiring chemical safety information for employees, and CPSC requirements requiring informative labeling for the public, as well as wearing hazmat suits when handling hazardous materials.

Packing groups are used for the purpose of determining the degree of protective packaging required for Dangerous Goods during transportation.

Group I: great danger, and most protective packaging required. Some combinations of different classes of dangerous goods on the same vehicle or in the same container are forbidden if one of the goods is Group I.[12]

Group II: medium danger

Group III: minor danger among regulated goods, and least protective packaging within the transportation requirement

One of the transport regulations is that, as an assistance during emergency situations, written instructions how to deal in such need to be carried and easily accessible in the driver’s cabin.[13]

A license or permit card for hazmat training must be presented when requested by officials.[citation needed]

Dangerous goods shipments also require a special declaration form prepared by the shipper. Among the information that is generally required includes the shipper's name and address; the consignee's name and address; descriptions of each of the dangerous goods, along with their quantity, classification, and packaging; and emergency contact information. Common formats include the one issued by the International Air Transport Association (IATA) for air shipments and the form by the International Maritime Organization (IMO) for sea cargo.[citation needed]